Switchably controlled liquid sealed type vibration isolator

ABSTRACT

A switched vibration isolator has an elastic base member fixed to a first fitting member, and a tubular member fixed the elastic base member. A partition device is disposed in the tubular member, and has an outer diameter, a first partition side opposing the elastic base member defining a main liquid chamber therebetween, and a second partition side opposite the first partition side. The partition device defines an orifice communicating with the main liquid chamber. A partition receiving plate has a diameter greater than an outer diameter of the partition device and the partition device is mounted thereon. A diaphragm is disposed opposing the partition receiving plate and defining an auxiliary liquid chamber communicated with the main liquid chamber via the orifice. The partition receiving plate and the diaphragm are fixed in place together by an end of the tubular member.

[0001] This is a continuation of Ser. No. 09/617,870, filed Jul. 17,2000.

BACKGROUND OF THE INVENTION

[0002] This invention relates to a switchably controlled liquid sealedtype vibration isolator used to support a power unit, such as anautomobile engine in a vibration isolating manner.

[0003] A switchably controlled liquid sealed type vibration isolatoradapted to switch vibration isolating characteristics thereof inaccordance with two kinds of vibrations in different frequency regions,such as shaking vibration and idling vibration, has been proposed as aliquid sealed type vibration isolator for use as a mount for supportinga vibrating body, such as an automobile engine, etc. so as not to havethe vibration of the vibrating body transmitted to a body of a vehicle.

[0004] For example, Japanese Patent Laid-Open No. 173372/1999 proposes aswitchably controlled liquid sealed type vibration isolator including ametal fixing member on a side of a vibration source, an outercylindrical metal member on a side of a support, a vibration isolatingbase member interposed between the two metal members and formed of anelastic rubber member, a first diaphragm fixed to the outer cylindricalmetal member so as to be opposed to the vibration isolating base member,and a partition provided between the diaphragm and vibration isolatingbase member, the partition and vibration isolating base member defininga main liquid chamber therebetween, the partition and first diaphragmforming therebetween a first auxiliary liquid chamber communicating withthe main liquid chamber via a first orifice, the partition beingprovided at a main liquid chamber-side portion thereof with a secondauxiliary liquid chamber communicating with the main liquid chamber viaa second orifice, and an atmospheric pressure and negative pressurechangeover chamber separated from the second auxiliary chamber via asecond diaphragm.

[0005] In this proposed liquid sealed type vibration isolator, thepartition is formed of a main partition member defining the firstorifice on an outer circumference thereof, and a partition plate memberdefining the second auxiliary chamber and orifice. The main partitionmember, to which the second diaphragm is fixed, forms the change-overchamber on the main liquid chamber-side portion and is fitted in aninner circumference of the outer cylindrical metal member. The partitionplate member is fitted around the diaphragm to hold a circumferentialedge portion thereof. Both the main partition member and partition platemember are installed held between a main liquid chamber-side surface ofthe vibration isolating base member and a liquid chamber-side steppedportion of the outer cylindrical metal member.

[0006] However, in the above-mentioned construction, the main partitionmember and partition plate member have to be installed submerged in aliquid in order by a press fitting method as orifice-communicatingopenings of both thereof are positioned. Therefore, the structure to beassembled is complicated, and, moreover, a high stability of thestructure is rarely obtained due to variations in accuracy of otherparts.

[0007] The main partition member and partition plate member are heldbetween the vibration isolating base member and the liquid chamber-sidestepped portion of the outer cylindrical metal member and therebyretained in a mere contacting state. Therefore, the predeterminedfunctions become unable to be fulfilled due to changes with the lapse oftime in the condition of the parts during the use of the vibrationisolator in a vehicle-mounted state. Such changes are ascribed to thefluctuation of a liquid pressure caused by the vibration of thevibration isolating base member, or permanent set in fatigue and slip ofthe rubber portions between the parts caused by the heat. The changesthus cause the sealing to become insufficient, and the passages workingas the orifices to be short-circuited.

[0008] The present invention has been made in view of these facts, andprovides a switchably controlled liquid sealed type vibration isolatorhaving a structure which permits an inner partition, by which an innerhollow space is divided into a main liquid chamber and two auxiliaryliquid chambers, to be assembled tentatively in an air environment,plural constituent parts to be combined together reliably and easilywithout being dislocated, and, moreover, the relative displacement ofthe constituent parts which occurs due to changes with the lapse of timeof themselves in a vehicle-mounted state to be reduced to a low level,whereby retention of an excellent sealed condition among the parts andthe improvement of the durability of the same parts are attained.

SUMMARY OF THE INVENTION

[0009] The present invention provides a switchably controlled liquidsealed type vibration isolator including a vibration isolating basemember formed of an elastic rubber member, a first metal fixing membercombined with one of upper and lower portions of the vibration isolatingbase member, a main cylindrical metal member combined with the otherportion of the vibration isolating base member, a first diaphragm fixedto the main metal member so as to be opposed to the vibration isolatingbase member, a partition provided between the vibration isolating basemember and first diaphragm, a main liquid chamber formed between thepartition and vibration isolating base member, a first auxiliary liquidchamber formed between the partition and first diaphragm, a secondauxiliary liquid chamber formed on a main liquid chamber-side portion ofthe partition, a change-over chamber separated from the second auxiliarychamber via a second diaphragm and capable of receiving therein anatmospheric pressure and a negative pressure in a switchable manner, andfirst and second orifices communicating the main liquid chamber with thefirst and second auxiliary chambers respectively, the vibration isolatorfurther having the following structure so as to solve the aforementionedproblems.

[0010] The partition has at an outer circumferential portion thereof amain partition member forming the first orifice, and the seconddiaphragm is provided on a main liquid chamber side portion of the mainpartition member so as to form the change-over chamber in adiametrically inner portion thereof. A partition plate member pressing acircumferential portion of the second diaphragm toward the mainpartition member to form the second auxiliary liquid chamber between thepartition plate member and the same diaphragm is engaged with and fittedfirmly around an outer circumferential portion of the main partitionmember by a swaging device for this outer circumferential portion. Aportion defined by the main partition member and partition plate memberon an outer side of the second auxiliary liquid chamber is formed as thesecond orifice. A partition receiving plate having an outercircumferential edge portion extending outward beyond an outer end ofthe main partition member is fixed by a press fitting device withrespect to the main partition member to the portion of the mainpartition member which is on the side of the first auxiliary liquidchamber. The partition plate member is fitted liquid-tightly in an innercircumferential portion of the main metal member, and the outercircumferential edge portion of the partition receiving plate is fixedwith the first diaphragm to the main metal member by a swaging member.

[0011] According to the liquid-sealed type vibration isolator of-thisconstruction, the structural parts of the partition incorporated in aninner portion thereof, i.e. the main partition member on an outercircumferential side of which the first orifice is formed, the seconddiaphragm forming the change-over chamber on the portion thereof whichis on the side of the main liquid chamber, the partition plate memberforming the second auxiliary chamber and orifice, and parts of thepartition receiving plate can be combined together in the air initiallywith ease and separately from the main metal member without causingthese members and parts to be dislocated. Therefore, after such atemporary combining operation, plural structural parts can be combinedaccurately by press fitting the partition plate member of the partitionfirmly into an inner circumference of the main metal member, and thenswaging the outer circumferential portion of the partition receivingplate with the first diaphragm to the main metal member, whereby aliquid sealed type vibration isolator provided with two auxiliary liquidchambers, two orifices and two diaphragms can be assembled easily.

[0012] Especially, since the partition plate member pressing the seconddiaphragm to form the second auxiliary liquid chamber and orifice isfitted firmly in an engaged state around the outer circumference of themain partition member by a swaging device for the same outercircumference, the main partition member and the main partition platemember are combined with each other without a fear of their beingseparated from each other. This enables the second diaphragm to bepressed reliably, and can prevent an excessive decrease in thesealability of the parts and the short-circuiting of the passage as anorifice which are ascribed to changes with the lapse of time in thevibration isolating base member during the use thereof.

[0013] In this liquid sealed type vibration isolator, a second metalfixing member covering a space on the outer side of the first diaphragmis provided, which is swaged with the partition receiving plate andfirst diaphragm to the main metal member, and these parts can also becombined together easily just as the above-mentioned parts.

[0014] In the liquid sealed type vibration isolators of each of theabove-described inventions, the main partition member is provided on theportion of an outer circumference thereof which is on the side of thefirst auxiliary liquid chamber with an orifice-forming recess, which aredefined by the partition receiving plate and main metal member to formthe first orifice. Therefore, the main partition member can bemanufactured easily, and is suitable for practicing the vibrationisolator.

[0015] The partition plate member is preferably formed by fitting firmlythe outer circumferential portion thereof around the outer circumferenceof the portion of the main partition member which is on the side of themain liquid chamber, bending at least a part of a circumferential endportion of the partition plate member inward in the above-mentionedorifice-forming recess, and swaging this bent portion to the mainpartition member. This enables the partition plate member to be swagedby utilizing the orifice-forming recess.

[0016] The circumferential end portion of the partition plate member canbe swaged at plural circumferentially spaced parts thereof to the mainpartition member, and also at substantially all parts of thecircumference thereof to the same member.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a longitudinal sectional view showing one embodiment ofthe switchably controlled liquid sealed type vibration isolatoraccording to the present invention;

[0018]FIG. 2 is a perspective view showing constituent parts, which arein a mutually separated state, of a partition in the same embodiment;

[0019]FIG. 3 is a sectional view of the constituent parts of FIG. 2 in aseparated state;

[0020]FIG. 4 is a sectional view of the constituent parts of FIG. 2 inan initially assembled state; and

[0021]FIG. 5 is a sectional view of a partition in another embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Preferred embodiments of the switchably controlled liquid sealedtype vibration isolator according to the present invention will now bedescribed with reference to the drawings but the present invention isnot limited to these embodiments.

[0023] Referring to FIGS. 1-4, a liquid sealed type vibration isolator Ahas a vibration isolating base member 2, formed of an elastic rubbermember which receives a load of a power unit, such as an engine, etc.The vibration isolating base member 2 is joined to an upper opened sideof a cylindrical main metal member 1, and a first metal fixing member 3.That is, the main metal member 1 is joined to the first metal fixingmember 3 via the vibration isolating base member 2. In the illustratedvibration isolator A, the vibration isolating base member 2 is formed ina substantially trapezoid-conical shape, and fixed air-tightly at anupper smaller-diameter end portion and a lower larger-diameter outercircumferential portion to the first metal fixing member 3 and theopened portion of the main metal member 1 respectively by avulcanization bonding device.

[0024] A first diaphragm 4, opposed to the vibration isolating basemember 2 and formed of a rubber film, and a second metal fixing member5, covering a an outer side of the first diaphragm 4, are fixed in asealed state at a lower opened side of the main metal member 1 by aswaging device to be described later. A reference numeral 41 denotes anannular reinforcing member vulcanization bonded to the diaphragm 4.

[0025] The first metal fixing member 3 is substantially disc-shaped, anda fixing bolt 31 fixed to a central portion of the first metal fixingmember by a press fitting device or a welding device projects upwardtherefrom, by which fixing bolt 31 the first metal fixing member 3 issecured to a power unit of an automobile.

[0026] The second metal fixing member 5 has a substantially cylindricalshape bottom wall portion 52, and a flange-like opened edge portion 51thereof is swaged with a partition, which will be described later, to alower end portion 1 a of the main metal member 1. The bottom wallportion 52 of the second metal fixing member 5 has a fixing bolt 53fitted therein by a press fitting device so that the fixing bolt 5projects downward therefrom. The second metal fixing member 5 is securedto a vehicle body-side member by the fixing bolt 53. A space between thesecond metal fixing member 5 and first diaphragm 4 is formed as an airchamber 6. This air chamber is communicated with the atmosphere in somecases, and formed as an air-tight chamber in some cases.

[0027] A partition 10 is air-tightly fitted in an inner circumference ofa portion of the main metal member 1 which is between the vibrationisolating base member 2 and first diaphragm 4, via a seal rubber layer 2a integral with the vibration isolating base member 2. An incompressibleliquid, such as water or ethylene glycol is sealed in an inner chamberbetween the vibration isolating base member 2 and the first diaphragm 4.This inner chamber is divided by the partition 10 so as to form a spacebetween the vibration isolating base member 2 and partition 10 as a mainliquid chamber 7, and a space between the first diaphragm 4 andpartition 10 as a first auxiliary liquid chamber 8. The portion of thepartition 10 which is on the side of the main liquid chamber 7 isprovided therein with a second auxiliary liquid chamber 9, a change-overchamber 12 which is separated from the second auxiliary liquid chamber 9by a second diaphragm 11, and which permits an atmospheric pressure anda negative pressure to be introduced thereinto switchably, and first andsecond orifices 13, 14 which communicate the main liquid chamber 7 withthe first and second auxiliary liquid chambers 8, 9 respectively, andwhich have different liquid passage resistances. In the illustratedembodiment, the first auxiliary liquid chamber 8 communicates with thefirst orifice 13 having a higher liquid passage resistance (smallercross-sectional area), and the second auxiliary chamber 9 communicateswith the second orifice 14 having a lower liquid passage resistance(larger cross-sectional area).

[0028] As shown in FIGS. 1-4, the partition 10 includes a main partitionmember 15, a partition plate member 16 and a partition receiving plate17, and has the following structure.

[0029] The main partition member 15 is made integral of a metalmaterial, such as aluminum, or a rigid material, such as a syntheticresin, and has an annular shape as shown in FIG. 2. The main partitionmember 15 is provided in a portion of an outer circumference thereof,which is on the side of the first auxiliary liquid chamber 8, with anorifice-forming recess 19 so that a portion 18 on the side of the mainliquid chamber 7 remains as a flange-shaped portion. The recess 19 isdefined by the partition receiving plate 17 and main metal member 1,whereby the recess 19 is formed as the first orifice 13 whichcommunicates the main liquid chamber 7 and the first auxiliary liquidchamber 8 with each other. The flange-shaped portion 18 is provided witha recessed communication section 13 a which communicates the firstorifice 13 and main liquid chamber 7 with each other.

[0030] An upper inner portion, which is on the side of the main liquidchamber 7, of the main partition member 15 has a second diaphragm 11. Anannular metal collar 20 is fixed to an outer circumferential portion ofof the second diaphragm 11 by a vulcanization bonding device. The seconddiaphragm 11 is fixed coaxially with the central axis by press fittingthe metal collar 20 into the main partition member 15. A clearancebetween the second diaphragm 11 and the main partition member 15 isformed as the change-over chamber 12 having a predetermined height. Areference numeral 12 a denotes a projection for maintaining theclearance of not smaller than a predetermined height.

[0031] In the illustrated embodiment, the central portion of an-uppersurface which corresponds to the change-over chamber 12 of the mainpartition member 15 is recessed curvilineally, and a groove 15 b forpress fitting the metal collar thereinto is formed around this recessedportion 15 a. The second diaphragm 11 is fixed to the main partitionmember so as to cover the recessed portion 15 a by press fitting themetal collar 20 into the groove 15 b.

[0032] The change-over chamber 12 is joined to a change-over device (notshown), such as a valve, etc. which can be switchably connected toeither a negative pressure source or an atmospheric pressure source viaa communication passage 21 extending through an inner portion of themain partition member 15 and communicating at a side surface of the mainmetal member 1 with an outer portion thereof. Thus, either a negativepressure or an atmospheric pressure can be introduced into thechange-over chamber 12 by operating the change-over device in accordancewith an instruction signal, etc. from a control unit.

[0033] As a result of the above arrangement, the second diaphragm 11 canbe controlled in a switching manner to an operating condition and anon-operating condition. In order to work mainly the second orifice 14of a lower liquid passage resistance (larger cross-sectional area), thesecond diaphragm 11 is maintained in a movable condition. In order towork the first orifice 13 of a higher liquid passage resistance, themovement of the second diaphragm 11 is stopped so as not to operate thesecond orifice 14 of a larger cross-sectional area. Thus, a sufficientdamping effect can be displayed with respect to vibrations in differentfrequency regions, by the respective orifices 13, 14.

[0034] The partition plate member 16 is a pressure molded product formedmainly of a steel plate, and has an annular projection 16 a on a lowersurface thereof. The partition plate member 16 is fitted firmly in themain liquid chamber 7 and engaged with the main partition member 15, asdescribed below, by a swaging device to engage the outer circumferenceof the main partition member 15 so as to seal the circumferential edgeportion 11 a of the second diaphragm 11 against the projection 16 a.Thus, a space between the partition plate member 16 and the diaphragm 11on an inner side of the projection 16 a is formed as the secondauxiliary liquid chamber 9. A space on an outer side of the secondauxiliary liquid chamber 9 and defined by the main partition member 15and partition plate member 16 forms the second orifice 14 communicatingthe main liquid chamber 7 and second auxiliary liquid chamber 9 witheach other via communication ports 23, 24 and has a comparatively largecross-sectional area. The first orifice 13 communicates with the mainliquid chamber 7 through the communication port 23 of the second orifice14. Namely, the first and second orifices 13, 14 have a common exit withrespect to the main liquid chamber 7.

[0035] The partition plate member 16 is engaged with and fitted firmlyaround the main partition member 15 by swaging the outer circumferentialportion 26 of the partition plate member 16 into a cylindrical portionof such a diameter that permits a cylindrical bent portion thus formedto be press fitted in the inner circumference of the main metal member1, fitting firmly the outer circumferential portion 26 around the outercircumference of the flange-shaped portion 18 by swaging into theorifice-forming recess 19 at least a part of the circumferential endsection 26 a of the outer circumferential portion 26 to thereby swagethe circumferential end section 26 a to the flange-shaped portion 18.

[0036] The swaging of the circumferential end section 26 a is donepreferably at substantially all parts of the circumference thereof,i.e., over the whole circumferential length of the recess 19 as shown inthe drawings but the circumferential end section 26 a can also be swagedpartially at plural portions thereof spaced from one another atpredetermined intervals to the main partition member 15. In this case,the portions to be swaged can be formed like projecting claws which areswaged.

[0037] The outer circumferential portion 26 is provided with one orplural circumferentially spaced openings 22 for carrying out easily thereplacement of air with a liquid when the partition plate member 16 isincorporated into the main metal member 1. The openings 22 are closedwith a seal rubber layer 2 a when the outer circumferential portion 26of the partition plate member 16 is fitted firmly in the innercircumference of the main metal member 1.

[0038] The partition receiving plate 17 is a pressure molded productobtained from a steel plate identical with the steel plate mentionedabove, having an opening in the central portion thereof and formed of adoughnut-shaped disc of a diameter slightly larger than that of the mainpartition member 15. The partition receiving plate 17 is positioned on aportion of the main partition member 15 which is on the side of thefirst auxiliary liquid chamber 8 and an opened edge portion 28 in acentral section thereof is press fitted into the recess 25 provided in alower surface of the main partition member 15. Thus, the outercircumferential edge portion 27 is fixed firmly projecting outwardbeyond an outer edge of the main partition member 15. In this condition,a recess 13 b, continuing from the recess 19, is aligned with an opening17 a so that the first orifice 13 communicates with the first auxiliaryliquid chamber 8.

[0039] In this structure, the partition 10 is in a initially assembledstate as shown in FIG. 4, in which the outer circumferential portion 26of the partition plate member 16 is press fitted liquid-tightly in theinner circumference of the main metal member 1 up to a position in whichthe outer circumferential portion 26 engages a circumferential edgeportion 2 b of the surface (lower surface in FIG. 1) on the side of themain liquid chamber 7 of the vibration isolating base member 2. Inaddition, the outer circumferential edge portion 27 of the partitionreceiving plate 17, the first diaphragm 4 having the reinforcing member41, and opened edge portion 51 of the second metal fixing member 5 areswaged together using the lower end portion 1 a of the main metal member1.

[0040] In the case of the illustrated embodiment, a larger diameterportion of the vibration isolating base member 2 has, at a part of acircumferential section thereof, a projection 2 c reinforced with a partof the main metal member 1. A stabilizer 29, fixed to the first metalfixing member 3 with a common tightening member, is disposed so as toextend near upper and lower surfaces of the projection 2 c, and functionas a stopper for restricting excessive vertical displacement of theprojection 2 c.

[0041] In order to assemble the liquid sealed type vibration isolator Aconstructed as described above, the metal collar 20 is press fitted intothe press fitting groove 15 b first, in the recess 15 a in the uppersurface of the main partition member 15 while in air, whereby the seconddiaphragm 11 is fixed so as to form the change-over chamber 12 betweenthe second diaphragm 11 and main partition member 15. The partitionplate member 16 is press fitted in an engaged state at the outercircumferential portion 26 thereof around the outer circumference of theflange-shaped portion 18 of the main partition member 15, and swagedthereto by a swaging member provided at the circumferential end section26 a of the outer circumferential portion 26. Thus, the circumferentialedge portion of the second diaphragm 11 is pressed by the projection 16a of the partition plate member 16, and the second auxiliary liquidchamber 9 and second orifice 14 are formed. The partition receivingplate 17 is fixed firmly at the press fitting portion in the centralportion thereof to a lower side portion of the main partition member 15which is on the side of the first auxiliary liquid chamber 8, wherebythe partition 10 is tentatively assembled as shown in FIG. 4. Duringthis time, the parts can be positioned as the positions of theorifice-forming openings and communication ports are ascertainedvisually with ease, and the tentative combining of the parts can be donereliably and easily without the parts being misplaced.

[0042] Next, the partition 10 assembled tentatively as described aboveis press fitted and combined in a liquid tank into and with the mainmetal member 1, which is vulcanization bonded to the vibration isolatingbase member 2 into a unitary body, as the air is discharged. During thistime, the outer circumferential portion 26 of the partition plate member16 is press fitted firmly and liquid-tightly in the inner circumferenceof the main metal member 1 via the seal rubber layer 2 a up to theposition in which the outer circumferential portion 26 engages thecircumferential edge portion 2 b of the main liquid chamber-side surface(lower surface in the drawings) of the vibration isolating base member2. After the air is extracted, the outer circumferential edge portion 27of the partition receiving plate 17, a portion of the first diaphragm 4including the reinforcing member 41, and the opened edge portion 51 ofthe second metal fixing member 5 are clamped together by swaging thelower end portion 1 a of the main metal member 1. A liquid entering thechange-over chamber 12 is discharged by taking out the same from theliquid tank. A rubber plug is inserted into the communication passage 21before the assembling of the vibration isolator so the change-overchamber 12 may be used by removing the rubber plug after the liquid istaken out from the liquid tank.

[0043] Accordingly, the switchably controlled liquid sealed typevibration isolator A of FIG. 1 is assembled easily and is formed so thata movement of the second diaphragm 11 on the side of the secondauxiliary chamber 9 can be switchably controlled to a moving conditionand a non-moving condition by a switching regulating operationintroducing a negative pressure and an atmospheric pressure into thechange-over chamber 12, which is provided along with the main liquidchamber 7, first and second auxiliary liquid chambers 8, 9, first andsecond orifices 13, 14, and first and second diaphragms 4, 11, and whichis adjacent to the second auxiliary liquid chamber 9 joined to thesecond orifice 11 of a lower liquid passage resistance.

[0044] In the vibration isolator thus assembled, the partition platemember 16 which presses the second diaphragm 11 to form the secondauxiliary liquid chamber 9 and second orifice 14 is fitted firmly in anengaged state around the outer circumference of the main partitionmember 15 by a swaging device for the same outer circumference.Therefore, the main partition member 15 and partition plate member 16are combined together thus preventing their being separated from eachother, and the second diaphragm 11 is retained in a pressed statereliably. Accordingly, even when the fluctuation of the liquid pressureascribed to the vibration of the vibration isolating base member 2, andpermanent set in fatigue of parts due to heat occur, there is not thepossibility that the deficiency of the sealability of parts and theshort-circuiting of orifices occur.

[0045] When the partition plate member 16 is swaged to the mainpartition member 15 as mentioned above, the circumferential edge portionof the second diaphragm 11 can be held in a clamped state between theprojection 16 a and the main partition member 15. Therefore, as shownin, for example, FIG. 5, this vibration isolator can also be practicedby clamping the circumferential edge portion of the second diaphragm 11by the projection 16 a and main partition member 15 with the metalcollar 20 of the second diaphragm 11 omitted.

[0046] As described above, in the switchably controlled liquid sealedtype vibration isolator according to the present invention, the innerpartition dividing the inner chamber into the main liquid chamber 7 andtwo auxiliary liquid chambers 8, 9, is formed so that the partition 10can be assembled initially in the air. This enables the pluralconstituent parts to be combined together reliably and easily withoutthe parts being mislocated. Furthermore, relative displacement of theconstituent parts in a vehicle-mounted state due to the variationthereof and the lapse of time is reduced, and the sealed condition ofthe parts is maintained in excellent condition, and contributes to theimprovement of the durability of the vibration isolator.

What is claimed is:
 1. A vibration isolator comprising: a fitting memberhaving a first portion for attachment to one of a vibrating body and asupport thereof and a second portion; an elastic base member having afirst side fixed to the second portion of the fitting member and asecond side; a tubular member having a first end fixed to the secondside of the elastic base member and a second end; a partition device,disposed in the tubular member, having an outer diameter, a firstpartition side opposing the elastic base member defining a main liquidchamber therebetween, and a second partition side opposite said firstpartition side, said partition device defining an orifice communicatingwith the main liquid chamber; a partition receiving plate having adiameter greater than the outer diameter of the partition device andhaving the partition device mounted thereon, the partition receivingplate having an annular portion extending beyond the outer diameter ofthe partition device, the partition receiving plate having an openingcommunicating with the orifice; a diaphragm disposed opposing thepartition receiving plate and defining an auxiliary liquid chambercommunicated with the main liquid chamber via said orifice; and saidannular portion of the partition receiving plate and said diaphragmbeing fixed in place together by said second end of the tubular memberswaged to clamp said annular portion and said diaphragm.
 2. A vibrationisolator comprising: a fitting member having a first portion forattachment to one of a vibrating body and a support thereof and a secondportion; an elastic base member having a first side fixed to the secondportion of the first fitting member and a second side; a tubular memberhaving a first end fixed to the second side of the elastic base memberand a second end; a partition device, disposed in the tubular member,having an outer diameter, a first partition side opposing the elasticbase member defining a main liquid chamber therebetween, and a secondpartition side opposite said first partition side, said partition devicedefining an orifice communicating with the main liquid chamber; apartition receiving plate having a diameter greater than the outerdiameter of the partition device and having the partition device mountedthereon, the partition receiving plate having an annular portionextending beyond the outer diameter of the partition device, thepartition receiving plate having an opening communicating with theorifice; a diaphragm disposed opposing the partition receiving plate anddefining an auxiliary liquid chamber communicated with the main liquidchamber via said orifice; another fitting member for attachment to theother one of the vibrating body and the support thereof, the anotherfitting member being disposed opposing said diaphragm to define acontrol pressure chamber; and said second end of said tubular member,said annular portion of the partition receiving plate, said diaphragm,and said another fitting member being mutually fixed in place together.3. The vibration isolator of claim 1 or 2, wherein said partition deviceincludes a recess at said second partition side, and said partitionreceiving plate includes a protrusion protruding towards said partitiondevice, said protrusion press fitted into said recess whereby saidpartition device is fixed to said partition receiving plate.
 4. Thevibration isolator of claim 3 further comprising another fitting memberfor attachment to the other one of the vibrating body and the supportthereof, the another fitting member having a flange clamped togetherwith said annular portion and said diaphragm by said second end of thetubular member.
 5. The vibration isolator according to claim 3, whereinthe diaphragm includes an annular reinforcing plate at a peripherythereof which is fixed along with the partition receiving plate.
 6. Thevibration isolator according to claim 3, wherein said second end of thetubular member is swaged to clamp said annular portion of said receivingplate, said diaphragm, and said another fitting member together.
 7. Thevibration isolator according to claim 6, wherein the diaphragm includesan annular reinforcing plate at a periphery thereof which is fixed alongwith the partition receiving plate.
 8. The vibration isolator accordingto claim 3, wherein the diaphragm includes an annular reinforcing plateat a periphery thereof which is fixed along with the partition receivingplate.
 9. A vibration isolator comprising: a fitting member having afirst portion for attachment to one of a vibrating body and a supportthereof and a second portion; an elastic base member having a first sidefixed to the second portion of the first fitting member and a secondside; a tubular member having a first end fixed to the second side ofthe elastic base member and a second end; a partition device, disposedin the tubular member, having an outer diameter, a first partition sideopposing the elastic base member defining a main liquid chambertherebetween, and a second partition side opposite said first partitionside, said partition device defining an orifice communicating with themain liquid chamber; said partition device including a main partitionmember and a partition plate, said partition plate forming the firstpartition side, defining an opening for the orifice to communicate withthe main liquid chamber, and having side portions fixed to a peripheralside of the main partition member and contacting an innercircumferential surface of the tubular member to seal the main liquidchamber with the exception of the orifice; a diaphragm disposed opposingthe second partition side and defining an auxiliary liquid chambercommunicated with the main liquid chamber via said orifice; anotherfitting member for attachment to the other one of the vibrating body andthe support thereof, the another fitting member being disposed opposingsaid diaphragm to define a control pressure chamber; and said second endof said tubular member, said diaphragm, and said another fitting memberbeing mutually fixed in place together.
 10. The vibration isolatoraccording to claim 9, wherein said second end of the tubular member isswaged to clamp said diaphragm, and said another fitting membertogether.